What counts as "decent"? I got RMS under 6, but some images were severely warped.

Note that APP sees the lens as 12mm, not 14.

Did a detection for 12mm rectangular lens, detection quality set to high. Image 1 linked to both 6 and 7 but not 2. Cleared the link from 1 to 6, added link from 1 to 2, optimized, set multiple viewpoints on and reoptimized.

APP seems to have issues with very wide rectilinear lenses, or perhaps wide rectilinear lenses distort the image to make it rectilinear, and APP "undistorts" it, then optimizes it.

Really short rectilinear focal length can be a bit more complicated to detect ( not to optimize in fact ).So, one solution that works quite well is to use ransac model 'homography' when having short focal length rectilinear lenses. It works better in detection.The rest ( meaning lens model, optimization ) is working great.

Issue 539 opened ( to check the case and confirm the above hypothesis )